Temperature evolution of spin-transfer switching in nonlocal spin valves with dipolar coupling

The spin-transfer effect has been achieved in nanoscale metallic nonlocal spin valves. A magnetic domain (∼70×150 nm2) in an extended wire can be switched by a pure spin current between 4.5 and 200 K. The dipolar coupling between the magnetic spin injector (F1) and spin detector (F2), the surface anisotropy of the thin F2 layer, and the thermal instability of F2 generates complex switching characteristics. Analysis of the results allows for detailed understanding of magnetic configurations during the current-sweep and the field-sweep measurements. The critical current (Ic) for spin-transfer switching gradually decreases as the temperature increases. The Ic+ for the transition from parallel (P) state to antiparallel (AP) state decreases faster than the Ic‐ for the transition from AP to P due to the dipolar coupling. Above 200 K, the dipolar coupling and the thermal instability prevents a stable P state in the absence of an external field.

► Reversible spin-transfer switching of a Py domain achieved in Py/Cu nonlocal spin valves.
► Both magnetic field-induced switching and current-induced switching observed over a temperature range of 4.5–200 K.
► Dipolar coupling, surface anisotropy, and the thermal instability generate complex switching characteristics.